I use a Cow shin for the bone. First I sawed the bone into pieces, then drew on the shape in pencil and sawed off the excess. The longest part of the job was trying to get the bone fairly flat, as the shin bone is round, so a long process of sanding the basic arrow head shape on some sand paper on a flat surface.
Once the basic shape was right, I then moved on to a course hand file and then on to some finer needle files for the final shaping. Last process was hand sanding with fine sand paper.
Next job will be to mount them on Arrow shafts.